-LRB- CNN -RRB- Debra Milke spent 22 years on death row , convicted of conspiring with two other men to kill her son allegedly for an insurance payout .

On Monday , a judge ruled that the Arizona woman is innocent and dismissed all charges against her .

This makes Milke only the second woman exonerated from death row in the United States .

More importantly , the judge 's decision finally clears Milke after years of legal back-and-forth in a case where she steadfastly maintained her innocence .

Key to the case 's dismissal was prosecutorial misconduct , mainly that of a detective , Armando Saldate , who said Milke confessed to the crime to him -- even though there was no witness or recording .

Prosecutors withheld from the jury Saldate 's personnel record which showed instances of misconduct in other cases , including lying under oath .

The two men with whom Milke was accused of conspiring were tried separately and are still on death row .

A day after seeing Santa Claus at a mall on December 1 , 1989 , young Christopher Milke asked his mother if he could go again .

Milke 's roomate , James Styers , took the boy ; then called Milke saying Christopher had disappeared .

Instead , Styers and a friend drove the boy out of town to a secluded ravine where Styers shot Christopher three times in the head , prosecutors said .

Styers and the friend were convicted of murder and sentenced to death .

Milke was implicated based on alleged testimony from Styer 's friend , Roger Scott .

The detective , Saldate , said Scott told him that Milke was involved in a plot to kill her son . And during her trial , prosecutors floated a likely motive : A $ 5,000 life insurance policy she had taken out on the child .

But neither Scott nor Styers testified to a plot in court .

No other witnesses or direct evidence linked Milke to the crime other than Saldate 's testimony .

Saldate further said that Milke confessed to her role in the murder plot during interrogation and said it was a `` bad judgment call . ''

There was no recording of the interrogation , no one else was in the room or watching from a two-way mirror , and Saldate said he threw away his notes shortly after completing his report .

Milke offered a vastly different view of the interrogation and denied that she had confessed to any role .

The trial became a he-said/she-said contest between the two .

Ultimately , the jury believed the detective and convicted Milke of murder .

What prosecutors did n't tell the court was the detective 's long history of lying under oath and misconduct .

Saldate had been suspended five days for taking `` liberties '' with a female motorist and lying about it to his supervisors . Four confessions or indictments had been tossed out because Saldate had lied under oath . Judges suppressed or vacated four other confessions because Saldate had violated a person 's constitutional rights .

In 2013 , after more than 20 years in jail , an appeals court overturned Milke 's conviction .

`` The Constitution requires a fair trial , '' Chief Judge Alex Kozinski of the federal 9th Circuit Court of Appeals wrote . `` This never happened in Milke 's case . ''

`` The state knew of the evidence in the personnel file and had an obligation to produce the documents , '' Kozinski said . '' ... There can be no doubt that the state failed in its constitutional obligation . ''

Milke was released on bail , and the court said she could n't be tried again .

The state appealed the decision to the Arizona Supreme Court .

Last week , the Arizona Supreme Court refused to hear the appeal . And on Monday , all charges against Milke were finally dropped .

The ankle bracelet she had been wearing while on bail was removed . And Milke left the court room , sobbing in relief .

The case is now closed . Debra Milke is finally a free woman .

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Debra Milke was convicted of murder in her son 's death , given the death penalty

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There was no evidence tying her to the crime , but a detective said she confessed

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This detective had a `` history of misconduct , '' including lying under oath